Pneumatic switch



A. ALLEN PNEUMATIC SWITCH Sept. 30, 1952 2,612,185

Filed March 14, 1951 2 SHEETS-SHEET l SIGNAL SIGNAL INPUT INPUT SIGNAL 1 OUTPUT SHUT-OFF PRESSURE GEAR VENT TO ATMOSPHERE FIG.- I

INVENTOR. flmszer 4LLEU I BY M mi EYS ; Albert Allen, Sharon, Mass assignorvto The Y. Foxboro Company,-Foxb,oro,-.Mass., ,a corporation ot TMassachusetts Application'March M, ms gserisl Na'icis'lsrz 1 .C la-im (o1. ;137e35) 5 This invention relates to instruments used :for indicating, recording, or controlling-with respect to variable conditionsrandha's particular ref- -erenceito pneumatic :systems; in -such;instruments.

The particular ,iprqblemiainvolved concerns the use of a plurality of- ,:'condition sensing *elements and :;pneumatic signals therefrom and 5 the selectionvof the particular signal or-signals "dev- The signal ,input -bo adaptor -7,

The inner end the seat l4; tandiimayibe contacted by the diaphragm 12. -.It; willv be. seen that such contact, funder propershut-ofi pressure, would aclose 'ofi; the.- 'signal'passage'fi, 'shutting ofi the pneumatic signal therein. I U

With further reference 'to' the adaptor, l4.,- ithe inner end thereof is reduced in outer diameter,

thus providing an annular opening 1-6 'aboutthe adaptorl .It follows that without the interference of the diaphragm (-2, the innermend ,of the signal .passage 15 would not be, blocked ,and the'input signal would .be transmitted out :of the innerend of the isignahpassage .15, over the inner 1nd X ofptheaadaptor14,- and backfliintogthe .anmr r c opening 16;

with-a :single, central, pneumatic output signal passage .l-Lcommon to. all of, the input-signals.

The common ;character of this output -;,pa-s sa,ge is accomplished byconnecting passages I;8 between It is an object of this invention tofiprovide a new and improved pneumatic switch.

Referring to the drawings, in which an illus trative embodiment of this invention is shown:

Figure I is a showing, in vertical central section, of a--pneumatic switch;

Figure II is a horizontal section whole upper body of the device showing the upper body only taken on a line as indicated by II-II in Figure I;

Figure III is a horizontal section through the whole lower body of the device, showing the lower body only, taken on a line as indicated by III--III in Figure I;

Figure IV is an elevation of a rotatable selector shaft which is shown in vertical central section in Figure I; and

Figure V is a horizontal section through the selector shaft, taken as on line VV in Figure IV.

Referring to Figure I, the pneumatic switch through the comprises, mainly a signal input body ill, 'a

each .iof ;-ithea :inpu-t; signal annular openm .and thegoutput passage 11;.

Whereas'rsixinputpassageslfiare shown', y I desired number'may be used. Thesinglei'dia- J I phragm l2 overlies the "inner-ends ,of {al l- .the v passages 1-5, and portions of the diaphragm; as will be shown, may separately and individually shut oif the signal-in such of the passages l5 as are selected for shut-ofi, while permitting a signal to pass from one of the passages l5... through a connecting passage l8 tothe common output passage H.

In other words, the diaphragm I2 isnot operated as a whole under a single pressure,- but the several portions of the diaphragm adjacent the innerv .ends of the input passages l5, may be operated singly or in concert to shut off certain of the passages I5, as desired. This is accomplished, as will be shown, through the passages and arrangements of the selector body H. The usual practice is to choose one of several input signals as the one desired in the output passage I1. The other signals are then shut off by the application of shut-oif pressure to the associated portions of the diaphragm while the shut-off pressure is not applied to that portion of the diaphragm which is associated with the signal selected for the output signal at that particular time.

With reference to Figures I and III, the selector body H is provided with a central opening l9, and a shut-off pressure inlet passage 20 leading to said opening. Shut-off pressure pas-sages 2| lead tflush withthe innervfaceaoi thexinput body Hi to iorm .a'valve dy 11-0 is further mama fr-om'the central opening l9 to the inner surface of the body H, each having an opening to that surfacein alignment with and adjacent to the inner end of one of the inlet passages l5 of the body I0," although separated therefrom by the diaphragmfl. The inner surface of the body ll is formed with cuplike. depressions gm about each of theshutoffpressureipassages 2|.ff These depressions receive'theadjacent portion of the diaphragm 12 when the shut-off pressure is not ap plied thereto. At this time the selected input sigsure passage 2|.

vented and the related diaphragm portion is na1 pressure is being transmitted through its inl I put passage 15, around the inner end of its adaptor l4, tolthe associated annular opening 16, and thence to the common output passage 1'! through the related connecting passage 18. 1

Referring to Figures I, IV, and V, in the central selector shaft 22 is mounted, with its inner end adjacent the diaphragm 12, and headed as at 23 to provide'a bearingfor the rotation of the shaft 22. The outer end of the shaft 22 is providediwith a gear 24;throughwhieh any'desired selector im-' pulse may be transmitted to the shaft 22 so' as to rotate it to such a position as willarrange :for the application ofshut -off pressure to all shuteolf portions of the diaphragm l2 except that' one which: is related to' thesign'al desired for. the output. e I I This selectio-n'is made possible by the particular c-onfiguration'of the selector sh-aft'22. This shaft,

initsnormal outside diameter, completelyfillsfth'e central opening I9 except for such clearance asis sure inlet passage 20. A second annular cutaway Eli-and ave'rtical slot 2! connecting the two annula'r cutaways, are provided'so the cutaway 25 is also open, at'any'one setting, to all buton'eof theshutfofi passages 2|. This one selected-passage'is blockedflfrom'the shut-off pressure by the normal'outer diameter of the selector shaft 22in its' close fitting association withthe-.central-opening I9," and because-the annular-cutaway 26 does the portion 28, Figure IV. lyforeover, the selector shaft 22 not completely encircle the shaft, as indicated by is provided with opening IQ of .the selector body ll, a rotatable v v an axial passage 29 as a vent to atmosphere, with a single radial venting passage 30 leading to the passage 29 through the portion 28. With this arrangement the passage 2| which is selected for venting, is connected to atmosphere through the passages 30 and 29.

To select a particular input signal, in body ID,

as lthexone desired in thebutput IT; the selector shaft 22 is rotated until' the radial venting passage 30 is aligned with the related shut-oil pres- The pressure therein is thus pushed into the related recess 2la in body II by *therelated' input signal pressure, and a passage 1 is provided to thepoutlet passages l8 and I! for this one, selected pneumatic signal. .signals',=as. exp1ained above, are all shut off by The other the application of shut-off pressure to the related portions of the diaphragm, forcing those portions need'ed 'for the rotation-of the shaft. However, there is'an annular cutaway portion 25, some pore 1 tion of'whichis always open to the shut-ofi pre-s-' over the inner ends of the signal openings I5. I'claim:' r l" l -A- pneumatic" switching device comprising a pair of bodies and-a diaphragm separating said bodies, one of said bodiescont-ainin a plurality of pneumatic signal input-'passagesextending to said diaphragm and closable thereby, and a common output passage connected" toeach of said in pu-t passages when 'notsh'ut oif by said dia phragm, and the other 'of said bodies containing shut-off pressure passages'to'said diaphragm adjacenteach of said inlet passages, and a rotatable selector shaft having a vent to atmosphere and a passage positionedby the rotation of said selector shaft to connect said vent passage with one of said shut-oil passages, said one of said shutoff passages being-thus selected not to receive said shut-01f pressure."

-' ALBERT ALLEN.-

Number Name 2,352,629 Griswold 'July 4, 1944 2,376,918 Hughes May 29, 1945 

